Inside the Allegheny Observatory, in a quiet, carpeted room off of one of the building’s rotundas, sits a telescope from the 1860s. Though the Observatory houses three working telescopes under three lofty domes — currently used to glimpse faraway nebulae and hunt for exoplanets — the smaller telescope points to the building’s more earthly origins. Known as a transit telescope, the apparatus was used to measure sidereal time, or “star time,” the basis for modern timekeeping.
At the Observatory, someone would sprawl out in a “comfy lounge chair, because [they] would spend the whole night laying under [the transit telescope],” explains outreach coordinator Kerry Handron, “looking at the stars crossing over” the sky.
Measuring stars’ positions enabled astronomers to calculate solar time, “the time that we use on a day-to-day basis,” says Handron, and the Observatory transmitted that time using a telegraph machine — also still on display today…